Various techniques may be used for testing vehicle systems and components during development and manufacturing. Various durability, lifespan, and performance requirements may be validated by static, quasi-static, and dynamic testing. Specifically, testing techniques that simulate a working environment may be utilized in order to determine whether components and systems perform their intended function during their lifespan. It is to be appreciated that long-term testing techniques may be required to validate components and relatively large systems, and sometimes the long-term testing may become costly.
Actuators are typically utilized when performing long-term or large-scale testing. The actuators may exert force on the systems and/or components being tested. The force exerted upon the components under test is expected to be accurately controlled. Furthermore, the actuators are expected to follow the motion of the component, without imposing uncharacteristic forces or restricting the motion of the component. For example, when testing an airfoil or wing of an aircraft, numerous actuators may be coupled to both the top and bottom sides of the wing. The actuators on the top and bottom side of the wing work in unison to flex the airfoil. Thus, when the wing is flexed in an upward direction, the actuators coupled to the top side of the wing follow the motion and velocity of the wing, without uncharacteristically restricting the movement of the wing while the actuators coupled to a bottom side of the wing are also exerting force in the upward direction.
Dynamic load control involves the accurate application of compressive and tensile forces to a moving object. When the load is exerted on the moving object using hydraulic actuators and servo valves based on classical control methods, sometimes the load may be inaccurate during maximum rated test conditions. Specifically, there may be inaccuracy in the force exerted upon the object relative to a commanded force signal, which is attributed to the motion of the object. As a result, the speed of the moving object may be reduced to obtain the desired force in order to stay within predetermined tolerance boundaries. Decreased speed results in longer test times and increased test expenses, particularly in long-term fatigue testing.
There is a need for reducing testing costs by increasing testing accuracy and, consequently, testing speed. Increasing testing speed of long-term testing may provide substantial reductions in testing expenses. However, attempting to increase the speed at which a test is performed may in turn increase the error as well. Furthermore, a number of testing procedures dictate a threshold error that the system may produce. If the system exceeds the threshold error, then the testing is terminated. The system may be adjusted before the testing may resume, which in turn increases testing time. Thus, there exists a need for a force control system that improves accuracy and also reduces the time required to perform a test.